C# lambda delegate type

using System;

class Example
{
   public static void Main()
   {

      //square becomes a delegate type
      Func<int, int>  square = x => x * x;
      Console.WriteLine(square(25));
   }
}
// The example displays the following output:
// 625

https://docs.microsoft.com/en-us/dotnet/csharp/lambda-expressions